The invention relates to a method for producing a riser for inserting into a casting mold used for casting metals, which riser consists of a riser body, which surrounds an inner cavity as a riser volume and is composed of an exothermic and/or insulating riser material, the riser body having a respective lateral wall region, a cover region, and a base region facing a mold cavity formed in the casting mold, wherein a riser opening is formed in the base region for connecting the inner cavity of the riser body with the mold cavity of the casting mold during the casting process and the inner cavity has, in at least a partial region, a diameter that is larger than the diameter of the riser opening, and wherein the riser body is produced by shooting in a core shooter. The invention further relates to a method for core box suitable for making a riser body for use in the core shooter.
In casting technology, it is often necessary to arranged additional risers in the casting molds, whose riser bodies fill with liquid metal during casting of the casting pieces and during solidification of the casting, compensate volume deficits that occur, in order to prevent formation of cavities in the casting piece. In this regard, the riser must be made, such that the liquid metal fed therein later solidifies as the casting piece, so that during the solidification process, a material transport to the casting piece can occur, which feeds the casting piece. In this connection, the riser is composed of an exothermic and/or insulating material. An important feature for the suitability of a riser is its riser module as a ratio of the riser volume to the surface of the riser, which is a geometrical ratio for the solidification rate of the metal introduced into the inner cavity of the riser during the casting process. The inner cavities of the risers frequently are cylindrically formed, which facilitates their manufacture in a core shooter, because the cylindrical shape of the inner cavity to be formed in the riser body means that there are no particular specifications for the formation of the corresponding shape for the core shooter. More advantageous with regard to the riser module, however, are inner cavities with a barrel or spherical design, wherein also more complicated cavity geometries can be sought based on considerations of casting technology, for example, with regard to a riser described in DE 295 10 068 U1.
Generally, these types of risers are related to a disadvantageously expensive manufacture, because the design of a cavity having an undercut design requires the use of corresponding core geometries in the shoot mold for making the riser when risers are manufactured in a core shooter. Since the unmolding of a riser body made as once piece from a shoot mold poses the problem of removing the core forming the inner cavity by means of the riser opening that has a smaller diameter than the inner cavity, such risers are made from two separate parts, which are combined to form a unitary riser body and connected to one another, preferably by adhesion.